Doing something Different(iated) for a change - Part 1

This post was spawned by a retweet of @edteck sent out by @shannoninottawa. The quote was

A thought...What % of your class time is spent having every kid do the exact same thing?

This seed was further nurtured by an article called "The School of One". The article describes the exact type of classroom I've always wanted to have. If you read the article, you'll find a broad range of responses, both for and against this approach.

Honestly, despite the potential chaos and confusion in the classroom and tons of extra work, I would love to have a classroom where all 30 kids were doing something entirely different every single day. Twenty years ago when I taught high school math, I taught two sections of what was then called Competency Math. These students had not passed the NC Competency test for math. I had 12 to 15 students in each class. Each student worked at his or her own pace until a particular skill was mastered. So why don't I do that now? What's my excuse?

Let me list my excuses first so I can shoot 'em down when I'm done.

1. I don't have the time. I'd have to come up with all my lesson plans, activities, etc. all at once so my quicker students would have something to do as they speed through.
2. I can't effectively teach every child that way. Somebody's going to fall through the cracks. The slower kids will probably get all the attention while the smarter kids teach themselves because they are able to anyway while the middle of the road kids get minimal instruction. Or I'll focus on the average kid because there are more of them and the advanced/slower kids will get neglected. Or . . .
3. I don't have the necessary resources. Sure, I did it 20 years ago, but honestly, it was really a worksheet driven class. Everything is tech driven today. I only have 1 computer in my room. Lab time is hard to come by. Besides, if everyone is doing something different, I cannot necessarily take them all to the lab at one time.

There are probably some other excuses but I'm sure they are some derivative of the above three.

1. Not everything has to be done at once. It would be nice to have everything all tidied up in a box, ready to pull as we progress through the year. I don't have to teach the entire course like this. I know what the standard course of study is for the year. Look ahead, pick a couple of units far enough in advance. Plan them around this philosophy and see how it goes. Expand the offering each year until you are satisfied.
2. Move to a student centered/learning driven classroom. Face it. Everything we do as teachers tends to be teacher centered and teacher driven. The emphasis is on how we present things, how we lead activities, how we deliver content. It's not about me - it's about the student. If I focus on the essential standards of my course instead of the myriads of factoids found in the content, all sorts of activities and lessons can be implemented. Give students every opportunity to create their own content so they can demonstrate mastery via evaluation, analysis, and other higher order skills. This will keep ALL students moving and learning.
3. 21st Century does not equal technology. 21st Century skills are skills like collaboration and evaluation, the same sort of skills we taught in the 20th century. True, they are pushed via technology today, but they don't have to be. You use it whenever you can get your hands on it, but come up with the old-fashioned ways all the other times. Check out this article by @kellyhines for more about that.

Okay, so I've eliminated all my excuses for myself. The next step is to actually do it. Part 2 will address that. While we all wait to see what that looks like, what other excuses am I missing? What are valid objections to such an approach? What are possible solutions?